Paradoxically, his dysfunction allows the narcissist to function. It compensates for lacks and deficiencies by exaggerating tendencies and traits. It is like the tactile sense of a blind person. In short: pathological narcissism is a result of over-sensitivity, the repression of overwhelming memories and experiences, and the suppression of inordinately strong negative feelings (e.g., hurt, envy, anger, or humiliation).
That the narcissist functions at all - is because of his pathology and thanks to it. The alternative is complete decompensation and integration.
In time, the narcissist learns how to leverage his pathology, how to use it to his advantage, how to deploy it in order to maximize benefits and utilities - in other words, how to transform his curse into a blessing.
Narcissists are obsessed by delusions of fantastic grandeur and superiority. As a result they are very competitive. They are strongly compelled - where others are merely motivated. They are driven, relentless, tireless, and ruthless. They often make it to the top. But even when they do not - they strive and fight and learn and climb and create and think and devise and design and conspire. Faced with a challenge - they are likely to do better than non-narcissists.
Yet, we often find that narcissists abandon their efforts in mid-stream, give up, vanish, lose interest, devalue former pursuits, fail, or slump. Why is that?
(From the book "Malignant Self-love: Narcissism Revisited" by Sam Vaknin - Click on this link to purchase the print book, or 16 e-books, or 3 DVDs with 16 hours of video lectures on narcissists, psychopaths, and abuse in relationships: http://www.narcissistic-abuse.com/thebook.html)